ESL systems typically include a plurality of ESLs for each merchandise item in a store. ESLs display the price of corresponding merchandise items on store shelves and are typically attached to a rail along the leading edge of the shelves. A store may contain thousands of ESLs to display the prices of the merchandise items. The ESLs are coupled to a central server where information about the ESLs is typically maintained in an ESL data file which contains ESL identification information and ESL merchandise item information. The central server sends messages, including register update messages, to the ESLs utilizing communication base stations (CBSs).
Communication between the CBSs and the ESLs is based on data being transferred utilizing a frame structure, with each frame being divided into timeslots. A typical retail establishment includes a plurality of CBSs, with groups of ESLs assigned to each CBS. Each ESL is associated with a particular CBS and assigned a particular timeslot, and listens for messages and transmits responses during that timeslot only, allowing a CBS to use different timeslots to communicate with different ESLs. A typical CBS may only use a subset of the available timeslots to communicate with ESLs during normal operation. If the ESL has been moved from its assigned physical location, the ESL may not be able to receive a message from the particular CBS that has been assigned to transmit messages to the ESL. Additionally, if the ESL has not been assigned a correct timeslot, the ESL may not be listening for messages at the appropriate time. Such situations effectively sever communication between the ESL and its associated CBS until the ESL can be found and corrective action taken. A suitable technique for automatically finding an ESL is described in U.S. application Ser. No. 10/044,439 entitled “Methods and Apparatus for Automatically Locating an Electronic Shelf Label” filed on the same date as the present application and incorporated by reference herein in its entirety. However, finding an ESL does not correct the problem of providing effective ongoing communication with the missing ESL. Therefore, it would be desirable to provide a system and method that automatically assigns an ESL to an appropriate CBS and timeslot after the ESL has been found.